Process for the manufacture of solid forms.



' S ms- PATENT OFFICE.

enoao EGLY, OF GHARLOTTENBURG, GERMANY, ASSIGNOR TO ennm'innn SIEMENS-6v 00.,

OF OHARLOTTENBUBG, NEAR. BERLIN, GERMANY.

To all whom it may concern: I v Be it known that I, Gnone EGLY, a-subject of the German Emperor, residing at 70 Kantstrasse, Charlottenburg, near Berlin, in the German Empire, chemist,

7 obtained. The material which 'is to constitute thel with nitrogen.

have invented certain new and useful Improvements in Processes for the Manufacture of Solid Forms, of

which the following is a specification.

This invention relates to a process for the manufacture of forms such as rods, tubes or disks,-of high electrical conductivity and great mechanical, thermal and chemical resistance, which can advantageously be used as electrical heating bodies and for other purposes,

such as for example, those requiring high mechanical resistance and hardness, like the manufacture. of grindstones.

' The process consists in mixing the material from which the form is to be made, with more or less silicon,

and if necessary with an agglutinant for obtaining the right-degree of plasticity; the desired form is fashioned, such as by pressing, from the mass made in this manner, and is thenheated in an atmosphere containing nitrogen, best in pure nitrogen, until a solid form is treatment with silicon, like carbon for instance. The most suitable mixture from which to fashion the form is one of silicon with silicon car-bid. Thesematerials are mixed as intimately as possible and treated in the manner already described. If a sufiiciently high pres- 'suitable solid form without the, aid of an agglutinant; when, however, one is necessary various sorts of agglutina'nts may be used to facilitate the fashioning of the sure is used the mass can generally be fashioned to a There may be used an agglutinsnt which is either completely volatilized by the high temperature which the form is afterwards subjected, or'comor partially left in the mass, for instance an agglutinant which is carbonized when heated, such as taror the like. i

The fashioned form is'introducedinto a suitable furme and heated for a considerable time in an atmos photo of nitrogen. The finished form contains a considerable proportion of nitrogen combined with ther 'while the silicon carbid, which in this instance been mixed'withthe silicon, has remained uni" and is strongly cemented by the silicon nitrid if a dense body. When an agglutinant that is moonss son 'rnn'uanursc'runn or sonmroaus.

Specification of. Letters-Patent; Patented Sept. 17, 1907. I Application filed December 2,1906. Serial No." 290,027;

capable of being carbonihed is used, there is formed,

according-to, the proportion of the carbon thus introf duced, a compound of. the composition C,Si,N. If a proportion of carbon cor-responding with this formula be added to the silicon, there is obtained a very solid f'mass whichconducts well and consists in the main of the compound C,Si,N; this compound, like the silicon nitrid firmly cements the silicon car-bid, for instance, with which it may be mixed.

The forms produced according to this invention have surprising properties. They can be heated in the open air to very high temperatures, such as 1000 C. and

higher, without being in the slightest degree changed. They are remarkably dense, hard and of high resistance; they may be used, for example, instead of carborundumfor grindstones and the like. They have unexpected electrical .conductivity and on this ,account, together with their aforesaid mechanical thermal and chemical resistance, are specially adapted for use as electrical heating bodies.

A rod consisting of G,Si,N, as described above, 125

cm. long and 1 square cm. in cross-section, has an electrical resistance of about 1 ohm. If the rod be fashioned from a mixture of 70 of silicon carbid and 30 parts of silicon and be heated in nitrogen in the manner described, it will have for the above dimensions, a resistance of about 20 ohms. If the mass consists of 70 parts of silicon carbid and 30 parts of silicon be mixed with 10 parts of clay, a rod of the same dimensions will have a resistance of about 70 ohms. On the other hand, if silicon carbid were mined with 10 per cent of clay without any siliconandbiirned in the ordinary manner, the form produced "would have a very high resistance, namely about 1000 onms, and mechanical properties much inferior to those of the forms made with aid of silicon and nitrogen according 'to. the present invention.

so i

Having now described the nature of my said invention and the best means I know' of carrying the same ,into practicaheffect, I claim:-

1. A process for the manufacture of solid forms which consists in'mixlng silicon with a material which is inert ht temperatures up to that at which silicon combines with nitrogen, fashioning the mixture into a. form, and heating the form in an atmosphere containing nitrbgen.

2. A process for the manufacture of solid forms-which consists in mixing silicon with silicon cal-bid, fashioning the mixture into a form, and heating the form in an nt- 4. A process for the manufacture of solid forms which consists in mixing silicon with silicon car-bid and an agglutinant, fashioning the mixture into a form, and heatat temperatures up to that at which silicon cornhines with ing the form in an atmosphere containlng nitrogen.

5. A process for the manufacture of solid forms which consists in mixing silicon with a material which is inert at temperatures up to that at which silicon combines with nitrogen and an agglntinant that carbonizes when heated,

* fashioning the mixture into a form. and heating the form 4 in an atmosphere containing nitrogen.

6. A process for the manufacture of solid forms which consists in mixing silicon with silicon carbid and an ngglutinant that carhonizeswhen heated, fashioning the mixture into a form and heating the form in an atmosphere containing nitrogen.

7. A process for the manufacture of solid forms which consists in mixing silicon with an agglutinant that carbonizes when heated, and with a material which is inert,

nitrogen, fashioning the mixture into a form, and heating the form in an atmosphere containing nitrogen.

8. A process for the manufacture of solid forms which consists in mixing silicon with a non-metallic substance and with a material which is inert at temperatures up to that at which silicon combineswith nitrogen, fashioning the mixture into a form, and heating the form in an atmosphere containing nitrogen.

in testimony whereof I have signed my mime to this specification in the presence of two subscribing witnesses.

HnNnr IlAsi-nu, Wowmm'n HAUPT. 

